Die apparatus



June 7, 1966 MCDONALD 3,254,550

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United States Patent 3,254,550 DIE APPARATUS John N. McDonald,McDonaldTool & Die Co., Inc., 2125 E. Rich, Spokane, Wash. Filed July21, 1964, Ser. No. 384,065 Claims. (Cl. 83128) This invention relates toa concentric die apparatus for stamping out sheet materials.

The present invention is concerned with a concentric or coaxial dieapparatus for use in a conventional die press, and is principallyconcerned with a die apparatus having long life, fast action and easilyreplaceable die and punch components. The present invention utilizes adie completely housed within a single rigid member, all of the movingcomponents of the apparatus being coaxially guided so as to insurecorrect alignment of the components.

It is a first object of this invention to provide such an apparatuswherein all of the moving parts being guided concentrically so that nopart of the die apparatus can become bent or misaligned during usethereof.

Another object of this invention is to provide such a die apparatus witha rigid supporting housing that surrounds the die and insures correctalignment of the moving components. This is in contrast with the normaldie that is supported by posts offset from the moving die and punchelements.

Another object of this invention is to provide such an apparatus capableof high speed Work on thin strip metal, the die apparatus being designedfor high volume punch operations.

Another object of this invention is to provide such a die apparatuswherein the basic components are to be considered as permanent, thevarious dies and punches being interchangeable on the apparatus whendesired.

These and further objects will be evident from a study ofthe followingdisclosure, taken together with the accompanying drawings which form apart of that disclosure. It is to be understood that this peculiar formof the invention is not intended to be the limit of its scope, theinvention itself being defined in the claims that follow thespecification.

In the drawings:

FIGURE 1 is a perspective view of the die as it would be used on. apress, a strip of the metal being utilized in the process being shown;

FIGURE 2 is'a front view of the die as seen from the left in FIGURE 1;

FIGURE 3 is a side view of the die as seen from the right in FIGURE 2;

FIGURE 4 is an enlarged bottom view of the die as seen along line 44 inFIGURE 2;

FIGURE 5 is an enlarged verticalsection view taken along line 55 inFIGURE 3;

FIGURE 6 is a sectional view taken at a reduced scale along line 6-6 inFIGURE 5;

FIGURE 7 is a sectional view taken at a reduced scale along line 77 inFIGURE 5;

FIGURE 8 is a sectional view taken at a reduced scale along line 8-8 inFIGURE 5;

FIGURE 9 is a sectional view at a reduced scale 'taken along line 99 inFIGURE 5;

FIGURE 10 is a fragmentary sectional view taken along line 1010 inFIGURE 5;

FIGURES 11 through 15 are a series of diagrammatic views similar toFIGURE 5 illustrating the operation of the die;

' die in its upper or initial position;

FIGURE 12 is a view similar to FIGURE 11 showing ing downward movementof the plunger prior to contact of the metal strip;

FIGURE 13 is a fragmentary section of the lower portion of the dieshowing the cutting of the strip by the respective die and plungercombinations;

FIGURE 14 is a view similar to FIGURE 11 showing upward movement of theplunger; and

FIGURE 15 is a view showing the stripping of the metal part from theinternal die aperture.

The present invention can best be understood from the disclosure inFIGURE 5, which is a sectional view taken through the entire apparatusand showing all of its basic components. The overall structure of thedie apparatus can be seen in FIGURES 1 through 4 which are externalviews thereof. FIGURES 6 through 10 are internal sectional views to showthe relation of the various components. Referring to these drawings, thedie apparatus constitutes a rigid supporting member including a base- 10extending upwardly from a plane base surface 8. Base 10 is provided witha transverse rectangular aperture 12 extending through its lowerportion. The transverse aperture 12 is in open communication with arectangular front opening 13, the purpose of which will be evidentshortly.

The base 10 is shown in a rectangular configuration in the as shown inFIGURES 1 through 3, the blocks 9 being then bolted or clamped to thebase of the press for support purposes.

The base 10 is also provided with a vertical aperture 14 that opens tothe transverse aperture 12. The vertical aperture 14 is a cylindricalupright aperture centered about a central verticalaxis in the base 10perpendicular to base surface 8. All of the various components to bedescribed below are also centered coaxially about this same axis, sothat all of the moving parts involved in this structure move coaxiallyparallel to the center longitudinal axis of base 10.

The base 10 isprovided with a circular retainer ring 16 at its uppersurface, the ring 16 being secured to the base 10 by a plurality ofrecessed screws 17 located about the periphery of the ring 16. The ring16 is provided with external threads that are engaged by internalthreads at the lower end of a cylindrical closed retainer cap 15 thatcovers the top of the base 10. The retainer cap 15 is mounted coaxiallyabout the axis described relative to the base 10. All of the movingparts of the apparatus are guided either within the base 10 or withinthe cap 15 so that none of the moving parts are exposed or mountedeccentrically relative to the central axis just described.

Mounted on the base 10 in a fixed location extending upwardly past thebottom surface of the transverse aperture 12'is a punch and die pad 11having an upwardly directed punch 18. Again, the cylindrical peripheryof the pad 11, as well as the periphery of the punch 18, is coaxial withthe upright central axis of base 10, which is perpendicular to the basesurface 8. The pad 11 is press fit within the base 10 and is removableby forcing it in a downward direction.

The punch 18 is surrounded by a stripper plate 22 having an aperturethat is complementary to the punch 18 so that the plate 22 can sliderelative to the punch 18 in a direction parallel to the axis of base 10.The plate 22 is limited in its upward movement by means of retainingPatented June 1966 i J) screws 23 (FIGURE 10) that threadably engage theplate 22 at their upper ends. The lower ends of the screws 23 areenlarged and slide within enlarged apertures 24. The

upward movement of the plate 22 is governed by the location of the topshoulders of the respective apertures 24, so that the plate 22 cannotmove upwardly beyond the position shown in FIGURES and 10. However, theplate 22 is free to move downwardly due to the relief provided betweenthe plate 22 and the pad 11.

There are provided a series of four biasing springs 25 recessed withinapertures 26 in the base and located about the surface of the plate 22in abutment with the lower surface thereof. The springs 25 are bottomedon recessed screws 27 threadably engaged with the aperture 26 andadjustable so as to allow adjustment of the spring pressure exerted onthe plate 22. Thus, the plate 22 will normally be maintained in theposition shown in FIG- URES 5 and 10, but can yield downwardly whennecessary. The purpose of the stripper plate 22 is to free the metalstrip or tape from the punch 18 after the desired work configuration hasbeen cut therefrom.

Mounted within the base 10 is a plunger 31. The plunger 31 is slidablymounted within a cylindrical collar 42 press fit within the verticalaperture 14 of the base 10. Sliding movement of the plunger 31 isfacilitated by means of a ball bearing collar assembly 43 ofconventional manufacture that separates the supporting cylindricalsurface 44 of plunger 31 and the collar 42. The collar assembly 43 has aplurality of longitudinally spaced circumferential rows of ball bearingsprojecting from it in rolling contact with both the interior surfaceconfiguration of collar 42 and the complementary exterior surfaceconfiguration of plunger 31. The purpose of the ball bearing assembly 43is to reduce frictional resistance to sliding movement and to insureproper operation of the device athigh constant speeds.

The plunger 31 is provided with a removable die 28 at its lower endsecured thereto by means of two screws 30. The die 28 has a die aperture45 that is complementary to the punch 18 and also, coaxial therewith.Located within the aperture 45 is a reciprocable stripper 37 slidablyguided by the aperture 45. Stripper 37 is biased upwardly by means of aspring 38 that surrounds its outside periphery within the plunger 31.The spring 38 bears upwardly against an enlargement 40 formed at the topend of the stripper 37. The stripper 37 bears upwardly against a flatcylindrical washer 41 which is contacted at its upper surface by meansof stripper push rods 32 that slidably extend along the full height ofthe plunger 31 within apertures cut therethrough.

There also is provided a fixed punch 36 that is press fit Within anaperture 46 formed through the center of the plunger 31. The punch 36 isalso coaxial and is designed to, punch out a section of the metal stripat the center of the main portion formed by the punch 18. Punch 36cooperates with a die aperture 20 at the center of the punch 18, whichextends through the height of the pad 11 and which is relieved at 21 topermit free movement of metal received therein after initial forming atthe top portion thereof. The punch 36 is fixed to the plunger 31 and thestripper 37 is free to reciprocate relative to the punch 36, as will beevident below.

The top end of the plunger has a cap 34 fixed to it and extendingradially outward therefrom. The cap 34 is fixed to the plunger 31 bymeans of a recessed screw 35 shown in dashed lines in FIGURE 6. The cap34- provides a radial shoulder against which the plunger spring 33 thatsurrounds the plunger 31 can push upwardly. The lower end of the spring33 bears against the retainer ring 16, so that the relatively heavyspring 33 normally biases the plunger 31 to an upward position, theinitial position of the apparatus being as shown in FIGURE 5.

There also is provided a hammer 47 that extends through an opening inthe retainer cap and which has a lower shoulder that bears against thetop of the cap 34 for transmission of force to the plunger 31 to causedownward motion thereof. The hammer 47 is provided with an axialextension 48 that fits within the aperture 46. The connection betweenthe extension 48 and the aperture 46 might be rather loose so that thehammer 48 can be replaced when desired. The apparatus as described andshown is readily adapted to a conventional die press withoutmodification of the press structure.

The operation of the die is rather simple and is best understood from astudy of the drawings as shown in FIG URES 11 through 12. In its initialposition shown in FIGURE ll, the lower surface of the stripper 37protrudes slightly beyond the lower surfaces of the punch 36 and die 28.The amount of protrusion of the stripper 37 should be slightly more thanthe thickness of the metal strip to be punched. The strip itself isdenoted by the numeral 50. It rests upon the stripper plate 22 and thepunch 18, the upper surfaces of both being coplanar at this time.

The initial downward movement of the plunger 31 releases the stripperpush rods 32, which had been in engagement with the inside surface ofthe retainer cap 15. This permits the spring 38 to push upwardly againstthe enlargement 40 and to cause the stripper 37 to recess slightly abovethe lower surfaces of the die 28 and punch 36, exposing the die apertureof the die 28 and the external periphery of the punch 36. The upwardmovement of the stripper 37 is restricted by the limited amount of freespace between the washer 41 and the lower inner surface of the plunger31 adjacent thereto.

Continued downward movement of the plunger 31 due to pressure on thehammer 48 causes the strip 50 to be punched as shown in FIGURE 13. Thedie 28 will press downwardly against the strip 50, causing the stripperplate 22 to move downwardly in opposition to the springs 25. Thepressure exerted upwardly by the springs 25 must be adjusted by means ofthe screws 27 to insure that this pressure will not cause the strip 50to spread. The downward movement of the die 28 over the punch 18 cutsthe outside configuration of the material desired, while the movement ofthe punch 36 within the die aperture 20 cuts the inside configuration,in this instance forming a circular washer with an inner hole. Thewashor is shown as 51, and the material removed from the hole is shownas 52. The washer 51 is then located within the die aperture of die 28and the material removed from the hole is located within the dieaperture 20.

Upward movement of the plunger 31 is illustrated in FIGURE 14, thewasher 51 remaining as described and the material removed from the hole,shown as 52, remaining within the aperture 20. The strip 50 is freedfrom the periphery of the punch 18 by the upward movement of thestripper plate 22, and is free to be reciprocated to its next positionas shown in FIGURE 15.

In FIGURE 15, the stripper push rods 32 have again abutted the upperinside surface of the retainer cap 15 and have caused the stripper 37 tomove downwardly relative to the die 28 and punch 36, thereby causing thewasher 51 to be removed from the die aperture. The washer 51 is thenblownfrom the die by means of an air nozzle 53 best seen in FIGURES 2,3, and 9. The nozzle 53 extends inwardly to a location in closeproximity to the plunger 31 and is located elevationally at the locationwherein the washer 51 will be stripped from the die aperture of die 28.The nozzle 53 can be connected to any conventional source of compressedair. The washer 51 is blown through the opening 13, while the strip 50moves intermittently through the transverse aperture 12 in base 10.Thus, the strip of metal 50 can be moved in an almost continuous cyclethrough the base 10, and the washers or other objects stamped therefromare blown out the front opening 13, the plunger 31 being thereforecapable of reciprocating along its central axis at the very rapid rateof speed.

While thedie apparatus as illustrated is designed fo mechanicaloperation on a conventional die press, the same apparatus could bereadily converted to hydraulic or pneumatic operation by utilizinghydraulic pressure or pneumatic pressure to reciprocate the plunger 31within the retainer cap 15. The cooperation between the various punchand die units would remain unaltered.

It is important to note that the die apertures and die members are alllocated coaxially within the rather heavy rigid base 10. Thus, the die28 can be readily removed by releasing the screws 30, and another die 28substituted in its place. Such substitution will also involve thesubstitution of the coaxial stripper 37. Punch 36 is alsointerchangeable, and can be eliminated where an internal hole in thefinished object is not desired. Also, the punch and die pad 11 ismounted coaxially within the base and it also can be interchanged withother pads 11 to complement the desired die 28, the stripper plate 22also being interchanged in such an instance. The important factor isthat all of these elements are mounted coaxially within the single base10,. so that they can be interchanged at will with other die and punchcombinations, allowing the basic die apparatus to be used in theformation of many different objects. There is no danger of misalignmentdue to the coaxial mounting of all of the elements within the singlerigid base member 10. This is to be contrasted with the normal die,which is mounted on posts offset from the die and punch, and which isnot capable of a high speed operation over long periods without someportion thereof being distorted and losing alignment. The present dieapparatus, when manufactured according to precision machiningtolerances, is capable of use over a long period of time to fabricatethousands of identical parts with an extremely high degree of accuracy.The apparatus has been used primarily in the stamping of washers orother circular elements from rather thin strips of metals, but quiteobviously the shape of the member being punched is not limited by anyphysical consideration relative to the apparatus. the coaxialrelationship existing between the parts be maintained for insuredaccuracy.

Various modifications might be made in the specific structureillustrated without deviating from the scope of the invention as it wasintended to be described. For this reason, only the following claims areintended to limit the scope of this invention.

'Having thus described my invention, I claim:

1. A die apparatus, comprising:

a rigid base member provided with a plane outside base surface and aninterior recess terminating within said base member short of said basesurface, said recess being bounded by an interior surface configurationperpendicular to said base surface;

said base member being further provided with a transverse aperture inopen communication with said recess at the end of said recess proximateto said base surface;

said base member including a releasable retainer cap enclosing theremaining end of said recess remote from said 'base surface;

a plunger mounted within said base member for reciprocable motionparallel to said wall surfaces, said plunger having an exterior surfaceconfiguration complementary to said interior surface configuration ofsaid base member and guided thereby;

said plunger having one end thereof projecting toward said retainer cap,the remaining end of said plunger being located within the transverseaperture of said base member;

a compression spring enclosed within said base member and encirclingsaid plunger, said spring being operatively engaged between said plungerand said base. member to urge said plunger toward said retainer cap;

It is only essential that 40 and complementary coaxial die and punchmembers formed respectively on said remaining endv of said plunger andon said base member in coaxial opposition to one another.

5 2. A die apparatus, comprising:

a rigid base member provided with a plane outside base surface and aninterior recess terminating within said base member short of said basesurface, said recess being bounded by an interior surface configurationperpendicular to said base surface;

said base member being further provided with a transverse aperture inopen communication with said recess at the end of said recess proximateto said base surface;

said base member including a releasable retainer cap enclosing theremaining end of said recess remote from said base surface;

a plunger mounted within said base member for reciprocable motion in adirection perpendicular to said base surface, said plunger having anexterior surface configuration complementary to said interior surfaceconfiguration of said base member and guided thereby;

said plunger having one end thereof projecting toward said retainer cap,the remaining end of said plunger being located within said aperture ofsaid base member and being provided with an axially apertured die memberfixed thereto;

a punch member fixed to said base member in axial 3 alignment with thedie member on said plunger, said punch member being complementary tosaid die member;

and first compression spring means enclosed within said base memberoperatively engaged between said base member and said plunger tonormally urge the plunger in a direction opposite to said base surface.

3. A die apparatus as defined in claim 2 further com prising:

a stripper member movably mounted on said plunger at said remaining endthereof, the'stripper member being formed with an exterior surfaceconfiguration complementary to the interior surface configuration of theaperture of said die member and slidably engaged therewith;

second compression spring means located within said plunger andencircling said stripper member operatively engaged between saidstripper member and said plunger to urge said stripper member inwardlytoward said one end of said plunger;

and a rigid rod slidably received through said plunger for axial motionperpendicular to said base surface, said rod having one end thereofprojecting through said one end of said plunger and the remaining endthereof in abutment with the stripper member.

4. A die apparatus as defined in claim 2 further comprising:

a stripper plate surrounding said punch, said stripper plate having anaxial aperture complementary to the punch and slidably mounted thereon;

. motion limiting means fixed to said base member in the path of motionof said stripper plate to limit movement of said stripper plate relativeto said base member in a direction toward said retainer cap;

and biasing means operatively connected between said base member andsaid stripper plate to normally ug: said stripper plate toward saidretainer cap.

5. A die apparatus as defined in claim 2, wherein said interior surfaceconfiguration of said base member and said exterior surfaceconfiguration of said plunger are cylindrical in shape;

and a ball bearing collar interposed between said interior surfaceconfiguration of said base member and said exterior surfaceconfiguration of said plunger having a plurality of longitudinallyspaced circumferential rows of ball bearings projecting therefrom2,627,212 2/1953 Conner et a1. 83-621 X in rolling cdntact with therespective surface con- 2,768,560 10/1956 Hirson 83-588 X figurations.3,143,015 8/1964 Luther et a1. 83-125 X 3,148,574 9/1964 Heigl et a1.83-618 X References Cited by the Examiner UNITED STATES PATENTS 5FOREIGN PATENTS 1,040,861 5/1953 France.

735,119 8/1903 Leavitt 83-125 X 1,236,338 8/1917 Miller 83-124 WILLIAMW. DYER, JR., Primary Examiner. 1428174 9/1922 Luther 83.424 I. M.MEISTER, Assistant Examiner.

2,576,295 11/1951 Good 83-125 X

1. A DIE APPARATUS, COMPRISING: A RIGID BASE MEMBER PROVIDED WITH APLANE OUTSIDE BASE SURFACE AND AN INTERIOR RECESS TERMINATING WITHINSAID BASE MEMBER SHORT OF SAID BASE SURFACE, SAID RECESS BEING BOUNDEDBY AN INTERIOR SURFACE CONFIGURATION PERPENDICULAR TO SAID BASE SURFACE;SAID BASE MEMBER BEING FURTHER PROVIDED WITH A TRANSVERSE APERTURE INOPEN COMMUNICATION WITH SAID RECESS AT THE END OF SAID RECESS PROXIMATETO SAID BASE SURFACE; SAID BASE MEMBER INCLUDING A RELEASABLE RETAINERCAP ENCLOSING THE REMAINIGN END OF SAID RECESS REMOTE FROM SAID BASESURFACE; A PLUNGER MOUNTED WITHIN SAID BASE MEMBER FOR RECIPROCABLEMOTION PARALLEL TO SAID WALL SURFACES, SAID PLUNGER HAVING AN EXTERIORSURFACE CONFIGURATION COMPLEMENTARY TO SAID INTERIOR SURFACECONFIGURATION OF SAID BASE MEMBER AND GUIDED THEREBY;